Small block Bench Racing (just for fun!)

[Peter M.]

To all,

A new question in my quest to learn about the amazing Corvette:

Since I am familiar with musclecars(having owned 6 ofer my lifetime) and the art of under/over exaggerating horsepower ratings:

Take the 65 L76 vs L79 vs L84 - do they run the same? Is one stronger than the other? If so, which?

Not having had the pleasure of driving any, do they all "feel" the same?

Finally, are these motors stronger than the LT1?

Thanks

Peter

[Richard D.]

Re: Small block Bench Racing (just for fun!)

Since getting my 68 327/350 HT, I've looked for some perfomance info. like 0-60mph and 1/4 mile times for that particular model, but have not come across any.

Anyone know what a stock converible would run with a 4 speed (M-20)and 3.70 gears? (No headers, stock exhaust, stock motor configuration).

It seems faster that the car I drive now with a factory spec of 7.6 sec. 0 - 60 mph, but I was just curious if anyone out there with the same set up in their 68 has timed it.

Rich

[Wayne K.]

Re: Small block Bench Racing (just for fun!)

Peter,

I've driven all mentioned and I've owned a 70 LT-1 and currently own a 67 L-79.
Except for the L-79 all are mechanical lifter motors therefore they sound much alike as far as engine noise goes. The L-79 does not pull in the upper RPMs like the others but a good running one has as good of mid range punch IMHO. I loved the LT-1 motor and that would be my overall small block favorite.

[Duke W.]

Re: Small block Bench Racing (just for fun!)

The '64 L-76 is decidedly "edgier" than the L-79. It does not have as much low end torque as the L-79, but pulls stronger in the top end. The 30-30 cam is the L-76 is "too big" - too much duration and overlap. The LT-1 cam was a considerable improvement - better torque bandwidth - especially more low and mid range torque end torque with a negligable sacrifice in top end power.

In 350 CID form a real LT-1 is stronger overall than any previous SHP 327 due to the combination of cam and longer stroke.

I recommend the LT-1 cam for all mechanical lifter SHP rebuilds or for those than want to convert a L-79 or medium performance engine to mechanical lifter SHP feel and performance.

Mechanical lifter SHP engines have a sound and "feel" that is incomparable. Once you experience it, you can never go back!

Duke

[Terry M.]

[Richard D.]

Re: Small block Bench Racing (just for fun!)

Would anyone have some numbers on performance for these motors?

0-60, 1/4 mi.?

Thanks,

Rich

[Tracy C.]

[Mike M.]

Re: Small block Bench Racing (just for fun!)

terry-- we are not losers( those of us hatched b/4 @ 1950) as we have experienced visceral sensations. the loosers are those born a.r.n(after ralph nader). regards, mike

[Duke W.]

Re: Just gotta ask, but I think I know the answer.

I highly recommend you install the LT-1 cam to maintain the original charater of your '63 L-76. It will idle and "feel" just like the Duntov cam, but be stronger across the rev range.

Chevrolet's recommended interval for checking valve lash is every 12K miles, so that's once every six year at your rate of mileage accumulation, and with a little experience it's a one hour job.

E-mail me and I will send you the procedure and rocker ratio adjusted lash specs for all SB mechanical lifter cams.

You can buy a repro LT-1 cam (3972178) and lifter kit from GMPP, but I don't have the kit part number handy. Also the cam from Federal Mogul Speed Pro is CS-1145R and use with the AT840R lifters. These are the "edge orifice" type lifter that was OE with small block cams. Some of the aftermarket cam vendors also sell a clone. My first choice is Speed Pro.

Be sure you use a NAPA/Echlin VC1810 or equivalent vacuum can. The OE can on the '63 SHP/FI engines in not properly matched to the cam.

Pocket porting, port matching the heads/manifold and a three angle valve job with .040" inlet seat width and .060" on the exhaust will improve top end power about eight percent without loss of low end torque and good valve seat longevity.

I believe you will regret not installing a mechanical lifter cam. A hydraulic cam will just not feel like a real L-76.

E-mail me if you want the adjustment procedure.

Duke

[Richard D.]

Re: Small block Bench Racing (just for fun!)

You said it Terry!

When I rip though the gears with the open top, well, there's not much to compare with that.

That's why I redid my 68.

I guess the numbers don't really matter that much since the grin says it all.

Was just curious though...

Rich

[Kevin #38315]

Re: Small block Bench Racing (just for fun!)

I just purchased a "G-Meter" from Escort (the same guys who make the Passport radar detectors), and plan to take it out with my 70 LT-1 /M-21. I'll report back what I find. It will report 0-30, 0-60 and 1/4 mi, as well as other data.

Kevin

[Dan Tewell]

Re: Just gotta ask, but I think I know the answer.

Tracy, The part number that Duke is refering to is 12364054. This is the blueprinted LT1 and matching lifters made by Crane Cams and sold through GM dealers. Cost for the kit is $145- $155.
Dan

[Dave McDufford]

Re: Small block Bench Racing (just for fun!)

The link below is to a Car & Driver archive that shows some of the road tests from back in the 60's.

A 65 convertible with 327/350, M21 and 3.36 gears did the quarter in 14.9 @ 94mph. 0 to 60 was 6.2 seconds.

Dave

http://corvette.caranddriver.com/timeline/index_1960s.asp

[Brian Monticello]

Re: Small block Bench Racing (just for fun!)

I tried to post this yesterday but botched the link.




http://www.spectracreations.com/corvette-101/perf.

[Chas Kingston]

Re: Small block Bench Racing (just for fun!)

My '69 350/350, upgraded to LT-1 specs, timed to 14 flat on street tires and closed exhaust. My '70 350/370 felt about the same. When I finally got that car running right, I let my neighbor take it for a ride. He returned with a BIG smile on his face. The '69 is shown on the link below.

Geezer